Reenforced sheet lead



GEORGE ,H. WOBRALL, F XIRKWOOD, MISSOURI.

BEENFORCED SHEET LEAD.

Application mea my a, 1924. serial No. 724,411.

' sheet lead.

Sheet lead` is used in the arts for various purposes, one of which is that of a lining which must' be chemically resistant; in suc a case the lining must'not only be fastened to its support but frequently must also be vide a duplex sheet made continuous by joining the edges ofthe sheet or sheets by burning. Chemical sheet lead, which is unalloyed Vllead, is satisfactory at low temperatures, but at high temperatures it is subject to expansion and contraction and because of its low elastic limit and low tensile strength, especially at the higher temperatures, it pulls and buckles so that the cross-sectionalarea or thickness of the sheet` is much reduced. 0n account of this fact, sheet lead especially when' subjected vto high temperatures, requires frequent repair and replacementwhich, on account of the high cost of material and the high cost of repair work, results in high cost of maintenance.

In order to overcome these objectionablefeatures of chemicalsheet lead, antimonial lead, which is lead alloyedI with antimony, has been used. While an antimonial lead sheet at a high temperature does not have the tendency to buckle that chemical sheet lead has, and has a higher elastic limit and higher tensile strength at higher temperatures, it readily disintegrates at a temperature above 150 F., especially when subjected to the action of acids. It has also been 4pro osed to'join a sheet of chemical lead wit a sheet of antimonial lead so as to prowith chemical lead on one'side and antimonial lead on the other. l-lowever on account of the dierences in the melting points of unalloyed lead and alloyed (antimony) lead, difficulties were encountered in the lead burning operations necessary to join the edges of the sheet or sheets, with the result that such a` duplex sheet was unsuccessful and its use abandoned.

Une of the objects of this invention, therefore, is to provide a composite article and more particularly ya reenforced lead sheet,

'having a body or' lead and a reenforcement enveloped by the lead, in order to attain the advantages of chemical lead whileincreasing its strength and elastic limit, especially at the higher temperatures.

Another object is to provide a composite article in which the reenforcement is welded to the lead so that there will be a .union therebetween.

.another object is to provide a composite article inA which the reent'orcement enveloped by the lead is ofsubstantially the same elongation as the lead so that the union between the lead and its reenforcement will be maintained.

Y Another object is to provide a process of making reenforced leads to secure the above objects.

' Further objects will appear from the detail description taken in connection with the accompanying drawing, in which:

Figure l is a perspective view of a mold for carrying on the process of producing the composite article embodying this invention;

Figure 2 is a perspective view of the lead slab;

Figure 3' is a the reenforcing ities therein;

igure 4 is an end View of a rolled sheet; an

Figure 5 is an enlarged detail edge view of a portion of a sheet.

In accordance with this invention the body of lead is provided with a reent'orcement whichvis enveloped by the lead as distinguished from simply being applied thereto in the form of another sheet. The reenforcement is, however, of such a character as to be of substantially the same elongation as the lead itself. Since, however, the purpose of the reenforcement is to strengthen the lead, the metal used should be one which has not only a higher tensile strength and higher elastic limit than lead, but this strength and limit must 'be maintained at higher temperatures. Moreover the reenforcement should be capable of forminor a weld or union` with the lead. A suitable perspective view showing metal poured into the cavmetal'which meets all'ofthese requirements is antmonial lead containing from 6 to l0 percent of'antimony. I

-In accordance with this invention a lead slab is cast with cavities therein and these .cavities preferably run along the slabl in substantially parallel relation. Into theseA cavities is thenpoured antimonial lead and this is preferably done while the slab is Still hot so that the body and the reenforcement willform a union or weld. The slab is then elongated in any suitable manner I out laterally, with the result that the compo. site'article will be a sheet having reenforcei asl being passed through rolls as in the manufacture of sheet lead, and this ro gis accomplished while the reenter-ced slab is still hot. The rolling is preferably in a direction along the reenforcements so that the bars of antimonial lead will become elongated with the lead body and flattened ments therealong. elongated therewith and welded thereto but enveloped by the lead. Referring now to the accompanying drawing, 1' designates a mold of any 4suitable construction mounted on a-base 2, Arranged `in this mold is a pair of spacers 3 which'are simply bars provided with holes to receive cores 4.` It willbe noted that these cores -are tapering to permit themto be withdrawn from the slab and that they alternatel extend with the smaller ends in opposite directions so as to secure a uniform sheet.

The Ymold 1 may be provided with manipulative elements 5, while the spacers 3 may be provided with similar manipulative elelfients 6.y It will be understood, of course, that the mold,`spacers and cores may be made of iron, steel or any other suitable inaterial. v

The chemical or unalloyed lead-is poured into the mold as shown in Figure 1, the

' mold taken off, the spacers withdrawn and the cores ushed out. This leaves a slab 7 as shown 1n Figure 2 provided with cavities 8 arranged therealong. This slab is then Seton end as shown in Figure 3 Aand antimonial lead poured into the cavities 8 so as to form bars 9 therealong. The antimonial lead is poured into the channelsas soon -as the slab .is chilled sufficiently to be solid and while it is still hot enough to form a' weld or union between the body andthe reenforcement of'the slab. As soon as the, antimonia), lead has ehillcdsuiiiciently to be 4solid, the reenforoed slab is rolled to the slgueezed out as more particularly shown, in'

gure 5, so that the bars are wider than theyy are thick and so that they taper `from their side edges to the middle.

)The result is, therefore, a composite sheet in whlch lthere 1s a continuous union between the reenforcement and the lead body where the reenforcements are enthe lead, the body and reenforceand in which these two are united by a welded union so as to form to all intents and urposes an integral structure. These reen orceinents may be nearer to one face than to the other of the sheet, as shown in A Figure 5, by placing the cores off center, so as to 'give a larger wearing surface to one fa'eelofy he reenforced sheet without -in any wayY impairing its structural strength and elastic limit. The strength of the resultant sheet is greatly increased by' the reenforcement. However, this reenforcement being enveloped bythe lead body, the exposure will be only of the chemical lead while 'the reenforcement will be protected against exposure. therewill be no creeping of the chemical lead with respect to the rcenforcement, even' with changing temperatures and even at high temperatures, so that 'there will be no c buckling of a sheet in that respect. Moreover since the' antimonial lead is not exposed, there will' be no disintegration, even if the sheet is exposed to acids at high temperatures. This sheet may be readily joined by burning since the reenforceinents are iinbedded and only exposed at theedges, while both faces to a considerable depth consist of chemicallead so thata sealed union may be formed by burning'. It has, therefpre, been found in practice that thecomposite article effectively overcomes creeping or crawling of lead sheets even at high temperatures and even vwhen subjectedto acids or other chemicals.- Furthermore the sheet may be read- ()n account of the welded union ily fastened vto its support .and since the reenforcements give the sheet its strength,

fewer fastener-s .may be employed while the sheet between the fasteners will maintain its shape. FurthermoreJ since the faces are of chemical'lead, such fasteners' may be covered by atches burned onto the faces o l? the sheet;- naccount of the greater strength of a sheet ofa given weight as compared vto the strength of angunreenforced lead sheet, a'thinner sheet maybe used for a given retiuiirement. This faetf together with the e eapness of antimonial lead, results in economy and` saving of material. Y

While there has been described and illustrated-one embodiment of this invention, it will be understood that this invention is capable ofother l embodiments than those described. Furthermore while in the speciflc embodiment-a rolled sheet has been described, it will be understood that other composite leadarticles having a body of lead and a reinforcement enveloped 'by the lead -maybe made in accordance with this invention; It will further be obvious that various changes may be made' in details without departing from the spirit of this invention; it is, therefore, to be understood that this invention is-not to be limited to the specific details shown anddescribed.

Having thus described the invention; what is claimed is:

1. A composite article having a body of lead and an enveloped reenforcement of a metal having a greater tensile strength at higher temperatures than'the lead and of .substantially the same elongation as the lead and welded thereto and therein.

2. A 'composite article having a body of lead and a reenforcement of lead alloy of substantially the same elongation as the lead and enveloped thereby.

A composite article having a body of lead and a reenforcement of antimonial lead of substantially the same elongation as the lead and enveloped thereby.

4. An elongated reenforced lead sheet in which the reenforcement is of a metal having 'a greater tensile strength at higher temperatures than the lead and of substantially the same elongation as the lead and is enveloped thereby.

5. An elongated reenforced lead sheet in which al lead alloy reenforcement is enveloped by the lead and Welded thereto and therein.

6. A composite sheet having a body of lead reenforced with lead alloy bars which and of substantially the same elongation in the lead vand elongating the lead and reenforcement together.

l0. The process of making reenforced lead sheets consisting in placing a r'eenforcement of a metal having a greater tensile strength at temperatures above normal than the lead in the lead while both are at a welding temperature and elongating the lead and reenforcement together.

11. The process of makingr reenforced lead sheets consisting in pouring a'reenforcing metal having a greater'tensilev strength at temperatures above normal than the lead into cavities in the lead and elongating the lead and reenforcement together.

12. The processof making reenforced lead sheets consistingin pouring a-reenforcing metal 'having a greatertensile strength vat temperatures above normal Vthan the lead into cavities in the lead while at a welding temperature and elongating the lead and reenforcement together.

13. The process of making reenforced lead sheets consisting in molding a lead slab With cavities therein, pouring a reent'orcing metal having a greater tensile strength at temperatures above nor-mal than the lead into the cavities and elongating the slab.

14. `The process of making reenforced lead sheets consisting in molding a lead slab with cavities therein, pouring a reenforcing metal having a greater tensile strength at temperatures above normal than the lead into the cavities While the slab is hot and elongating the slab.

15. The process of making reenforced lead sheets consisting in placing reenforcing bars of a metal having a greater tensile strength at temperatures above normal than the lead and of substantially the same elongation, in the lead and rolling the lead and reenforcement down to the desired thickness.

sheets consisting in placing reenforcing bars of a metal having a greater tensile strength at temperatures above normal than the llead and of substantially the same elongation, in

a5 16. The process of making reenforced leadl `the lead and rolling the lead and reenforce- A ment in a direction along the bars down to the desired thickness.

17. The process of making reenforced lead sheets consisting in placing reenforcingbars of a metal having a greater tensile strength at temperatures above normal than th'e'lead,

in the lead and rolling the lead and re- I enforcement while hot down to the desired thickness.

18. The process of making reenforced lead sheets consisting in molding a lead slab with `channels therealong, pouring the reenforcing metal into lthe channels and rolling the slab. down to the desired thickness.

19. The process of making reenforced lead sheets consisting in molding a lead slab with channels therealong, pouring the reenforcin metal into the channels and rolling the sla in a direction along the reenforcing metal down to desired thickness. Y

20. The process of making reenforced lead sheets consisting in molding a lead slab with channels therealong, pouring the reenforcing metal into the channels while the'slab is hot and rolling the slab while hot but in a direction alon the reenforcing metal down to the desired ckness.

In testimony whereof I aiiix my signature l 

